Antioxidant defenses in aqueous humor and blood of patients with exfoliation syndrome glaucoma

FERREIRA, S.; REPETTO, M.; LERNER, F.; BRUNZINI, R.; EVELSON, P.; LLESUY, S.

Aguas de Lindoia, San Pablo, Brasil.

Congreso; IV Meeting of the South American Group of the Society for Free Radical Biology and Medicine; 2005

South American Group of the Society for Free Radical Biology and Medicine

Purpose: Oxidative stress and antioxidants systems may be associated with glaucomatous damage. The aim of the present study was to establish the antioxidant status of the aqueous humor and blood in Exfoliation Syndrome Glaucoma patients in comparison with a control group. For this purpose we studied the activities of antioxidant defense enzymes superoxide dismutase (SOD), catalase and glutathione peroxidase (GPx) in aqueous humor and the total reactive antioxidant potential (TRAP). Methods: Aqueous humor was obtained at the time of glaucoma surgery from 18 patients with Exfoliaton Syndrome Glaucoma (GPXE) and 24 control patients. The activity of the antioxidant enzymes was measured spectrophotometrically. SOD was determined by measuring the inhibition in the rate of adrenochrome formation at 480 nm. Catalase was evaluated by measuring the decrease in absorbance at 240 nm. GPx was determined following NADPH oxidation at 340 nm. TRAP was measured by chemiluminiscence. Results: An increase in SOD activity was observed in glaucoma patients (44.2 ± 6.7 U SOD / mL) when compared with control patients (26.5± 0.6 U SOD / mL p< 0.0001). GPx activity was 3 fold higher in glaucoma patients than in the control group (6.1 ± 0.6 U / mL p<0.0001). No significant changes were found in catalase levels. TRAP values of GPXE group was 66 ± 13 µM Trolox. This value was significantly decreased, by 35 %, in glaucoma patients than in control group (124 ± 5 µM p< 0.0001). The antioxidant status of the aqueous humor in Exfoliation Syndrome Glaucoma patients has significant changes in comparison control group. Conclusion: SOD and GPX were increased in the aqueous humor of Exfoliation Syndrome Glaucoma and a decrease of the total antioxidant capacity was measured. TRAP, GPX and SOD activities may be useful oxidative stress markers in the aqueous humor of GPXE patients. Oxidative stress may lead to the induction of antioxidant enzymes and contribute to the observed TRAP decrease.